Translating device



Jan; 31, 1933. 5 w. GENT 1,895,757

TRANSLATING DEVICE Filed Feb. 27, 1931 2 Sheets-Sheet 1 FIG. 4

' I 4s 43 5 2 0 0 /3 r o 5/ g 7 53 so I o r F\\ ATTORNEY Jan. 31, 1933. E. w GENT 1,895,757

\ TRANSLATING DEVICE Filed Feb. 27,1931 I 2 Sheets-Sheet 2 FIG. 4

INVENTOR E. W GENT ATTORNEY Patented Jan. 31, 1933 UNITED STATES PATENT OFFICE EDGAR W. GENT, OI HOBBISTOWN, NEW JERSEY, ASBIGNOB 'lO BELL TELEPHONE LABORATORIES, INOOBZOBATED, 01' NEW YORK, N. Y A CORPORATION Oil-NEW YOBI rnmsna'rmo DEVICE Application filed l'ebluflfy a7, 1931. Serial in. 518,741.

l. The objects are to facilitate the mounting and adjustment of the vibratory elements of a light valve, to enable the replacement of these elements without disturbing other parts of the device, to secure a simplified and more complete unit. In other words, the magnetscompact magnetic structure, and to otherwise improve ap aratus of this nature.

Heretofore in ight v'alves employing vibratory strings or ribbons, it has been the practice to sup ly the necessary magnetic field means of e ectromagnets having two pole p1eces with a light-transmitting slot passing therethrough. Usually one of these pole pieces was mounted on one part of the structure and the other pole piece on another part, the latter of which was removable for the purpose of mounting and adjusting the viratory ribbons. With such a construction it was necessary to disassemble the magnetic structure by removing one pole piece from its cooperative relation with the other in order to re lace or adjust the vibratory ribbons. Accor ing to the present invention, these objections are overcome by means of a device in which the magnetic structure forms one complete unit and the vibrator string or ribbon structure forms a secon and separate and pole pieces which furnish the ma etic flux 1n the region of the light-transmitting slot are mounted and securely fastened to a main mounting frame. The vibratory ribbons are mounted on a secondary or separate mounting frame which is provided with adjusting means whereby the necessary spacing adjustment and tension ad'ustment may be made before assembly. A ter these adjustments have been completed, the secondary frame comprising the ribbon unit is detachably secured to the main frame to bring the ribbon into cooperative relation with the light transmitting slot and pole pieces.

A feature of the invention is a structure of this kind in which it is possible to use permanent magnets to supply the magnetic flux for the valve. Although these magnets setup a stron flux, which is constantly present, such flux oes not interfere with the removal of the ribbon unit for replacement and adustment since it is not necessary for this purpose to withdraw either pole piece from its fixed position with respect to the other pole piece.

In the drawings accompanying this specification, Fig.1 is a sectional view showing a portion of a sound recording device including the li ht valve embodying the present invention; ig. 2 is a perspective view on an enlarged scale illustrating the manner in which the parts of the light valve are assembled;

Fig. 3 is a plan view also on an enlarged scale showing more clearl the arrangement of the vibratory ribbons; ig. 4 is a sectional view similar to the one shown in Fi 1 involving a modified form of light valve; ig. 5 is a pers ective view showing the way in which the ribbon unit is assembled; and Fi 6, 7 and 8 are details of the vibratory ri bon structure.

The present light valve is particularly useful for recording sound on moving picture film although it may. also be employed for recording pictures and views. The invention is an improvement in light valves of the general type disclosed in the co ending application by E. W. Gent and lotts, Serial No. 336,474, filed January 31, 1929.

Referring first to Figs. '1, 2 and 3, the structure may be regarded as comprising two separate parts, the magnetic unit and the vibratory ribbon unit. The main frame 1, constructed in the form of a housing, serves as the support and container for the permanent .magnets 2 and 3 comprising the magnetic unit. For clearness of illustration this portion of the device is shown in Fig. 1 rotated through an angle of The permanent main frame 1 is are rovided with light-transmitting slots whic register accurately with each other at the air-gap 12. These slots are outlined by the dotted lines in Fig. 1, and one or them is seen more clearly in Fig. 2.

The vibratory ribbon unit shown in Figs. 2 and 3 com rises a separate auxiliary mounting frame 1 7. This support 17 carries a air of ribbon suspending bridges. One of t ese bridges includes the supporting elements 20 and 21, and the other bridgeincludes the supporting elements 22 and 23. The tipsof these bridges are equipped with locating pins 24, 25 and 26, 27 embedded in insu ating material to prevent electrical short-circuitin of the parallel sections of the ribbon. The vi )ratory ribbon 40 is secured to the mounting plate 17 by means of two tension springs 28 and 29 and a loop anchor in the form of an idler pulley 41. One of the free ends of the ribbon is secured to the tension spring 28. From the spring 28 it passes over the bridge members 23 and 21, being located in proper position by the pins 26 and 24, thence around the pulley 41 and returning over the bridge members 20 and 22, being located by the pins 25 and 27, to the other tension spring 29. The tension springs 28 and 29 are adjustable by means of screws 30 and 31 respectively, in order to give the ribbon the proper tension. The spacing of the two parallel sections of the ribbon is controlled by the adjusting screws 36 and 37. The tension springs 28 and 29 are electrically connected res ectively to the terminal plugs 32 and 33 which project slightly beyond the edge of the frame 17.

After the ribbon has'been mounted and adjusted on its supporting frame 17, the said frame 17 is then assembled with respect to the main frame 1. 'It will be noted that the provided with two projecting arms 13 and 14 integrally formed therewith. The supporting arm 13 is provided with a tongue 15 and the arm 14 with a tongue 16. It will also be noted that the auxiliary frame 17 is provided with grooves 18 and 19 which register respectively with the tongues 15 and 16. The frame 17 has a rectangular portion 38 cut away to a suificient depth to receive the pole piece 10 as the frame 17 slides into place y means of the "tongue and groove connection. With the frame 17 fully in place the assembled and adjusted ribbons are brought to rest exactly in proper relation with respect to the light-transmitting slots in the pole pieces 10 and 11.

With the parts thus assembled the connecting plugs 32 and 33 enter the jacks 34 and 35 whereby the ribbon operating currents may be brought in from the outside of the structure.

The optical system with which the light valve is associated includes a source of light 47 and lenses 48, 49, 50 and 51. The lenses 48 and 49 are secured in' the housing 1, which in turn is removably secured to the member 43. The member 43 is attached to the sup orting frame 44 by means of bolts 45 an 46. The lenses and 51 are adjustably mounted within the member 43. Light from the source 47 passes through lenses 48, 49 and the-1i httransmitting slot in the pole pieces 10 an 11, and thence through the lenses 50 and 51, through an aperture in the aperture plate 52 where it encounters themoving film 54 held in position by the presser foot 53. The film 54 is driven y a sprocket 55 in any convenient manner the tension element 56 serving to hold the film against the sprocket.

A description will now be given of the alternative construction shownin Figs. 4 to 8 inclusive. In this device the magnetic unit, including the housing member 65, permanent magnets 66 and 67, and pole pieces 68 and 69, is substantially .the same as that shown in Fig. 1. 'The ribbon unit, however, comprises a mounting frame 70 of right-angled formation. In this case the vibratory ribbon 71 is secured at one end to the tension gri 72 from whence it passes over the bridge 3, being located by the pin 74, thence around the anchor plate 76 and returning to the bridge 73 where it is located by the pin 75 and thence to the other tension grip 77. The anchor plate 76 comprises two thicknesses 78 and 79 of some suitable material such as duralumin having a thickness of about .002 inch. The thickness 78 has a small ear 80 upturned within an aperture cut through both thicknesses 78 and 79 as seen in Figs. 6 and 7. The ribbon 71 is secured to this anchor plate as seen in,

Figs. 6 and 7 by first passing it between the thicknesses 78 and 79 on one side of. the ear 80, thence to the exterior through aperture 81, around both thicknesses 78 and 79, back through the aperture 81 and between the two thicknesses on the other side of the ear 80 and thence to the bridge 73. This gives an accurate spacing of the sections of the ribbon of about .002 inch. The bridge 73 is adjustable to secure the proper spacing of the ribbon sections by means of adjm .in screws 89 and 90. The tension grips 72 and 77 are electrically connected to the plug members 82 and 83.

The magnetic and ribbon units in this structure are assembled in a manner similar to that disclosed in Figs. 1, 2 and 3. The main frame 65 is equipped with tongued supporting arms 85 and 86 which match with the grooves 87 and 88 in the frame 70.

T e optical system in Fig. 4 is similar to that shown in Fig. 1. The light beam produced by the lamp 91 passes through the various lenses and the light-transmitting slot and is directed to the moving film 92 on which the record is produced.

With a light valve of the construction explained herein, it is possible to completely facilitate replacement and adjustment without interfering with the magnetic circuit. Since the pole pieces 10 and 11 in Fig. 1, for example, do not need to be disturbed to enable replacement and adjustment of the ribbon, permanent magnets may be employed instead of the electromagnets. This greatly sim-' plifies the equipment necessary for apparatus of this kind.

What is claimed is:

1. The combination in a translating device of a pair of pole pieces formed to define a light-transmitting slot, a mounting member to which said pole pieces are secured in operative relation to each other, a vibratory element for controlling the passage of light through said slot, a second mounting member to which said vibratory element is secured,

and means for detachably securing said sec,

ond mounting member to said first mounting member to locate said vibratory member in operative relation to said light-transmitting slot.

2. The combination in a light valve of a pair of pole pieces having a light-transmitlight-transmittin slot, a main mounting member to which said pole. pieces are attached, an auxiliary mountin member a vibratory ribbon on said aux iary member for controllin the passage of light through said slot sai main mounting member and said auxiliary member being provided with tonguedand grooved portions to rmit said auxiliary member to be detacha ly secured to said main mounting member to locate said ribloon with respect to said light-transmitting s o In witness whereof, I hereunto subscribe my name this 20th day of February 1931.

a EDGAR w. GENT.

ting slot passing therethrough, a mounting frame to which said pole pieces are secured a in operative relation to each other, a vibratory ribbon for controlling the passage of light through said slot, a second mounting frame to which said ribbon is secured, means on said second frame for adjirsting said ribbon, and means for detachably securing said second frame to said first mentioned frame to bring said ribbon into operative relation with said light-transmitting slot.

3. The combination in a translating device of a magnetic structure comprising magnets and pole pieces therefor, said pole pieces having a light-transmitting aperture therein, a housingand mounting frame to whichsaid magnets and pole pieces are secured, an auxiliary mounting frame, a pair of vibratory ribbons secured tosaid auxiliary frame and traversing said aperture to control the density of the light transmitted tiherethrough, means on said auxiliary frame for adjusting the tension and spacing of said ribbons, and means for detachably securing said auxiliary frame to said housing and mounting frame.

4. In a light valve, a main mounting frame, a magnetic structure comprising permanent magnets and pole pieces securely attached to said mounting frame, said pole pieces having a light-transmitting aperture therein, an auxiliary mounting frame, a vibratory element secured to said auxiliary frame and traversing said aperture to define the o ening through which light is transmitte and means for detachably securing said auxiliary frame to said main mounting frame to locate said vibratory element with respect to said light-transmitting aperture.

5. The combination in a translating device of a pair of pole pieces formed to define a y 

